Dictionary
o•blig•a•to•ry
Pronunciation: (u-blig'u-tôr"ē, -tōr"ē, ob'li-gu-), [key]—
adj.
1. required as a matter of obligation; mandatory:
A reply is desirable but not obligatory.
2. incumbent or compulsory (usually fol. by
on or
upon):
duties obligatory on all.
3. imposing moral or legal obligation; binding:
an obligatory promise.
4. creating or recording an obligation, as a document.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.